SIMBAD: Description of measurement types


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1  Chapter G. Description of measurement types

  1. Overview
  2. diameter measurements
  3. distance measurements
  4. Fe/H Measurements
  5. ISO measurements
  6. IUE measurements
  7. MK measurements
  8. PLX measurements
  9. PM measurements
  10. ROT measurements
  11. V* measurements


2  Overview

Each type of data listed as a result of a SIMBAD interrogation is normally preceded by a header which provides a very short title to each listed parameter. This chapter explains the meaning of each of these titles.

Note: the character ~ in a field stands for no corresponding value (unknown value).

The following measurement types are presently included in SIMBAD:

 
diameter Stellar diameter distance Objects distance ISO Infrared Space Observatory (Observation Log) IUE International Ultraviolet Explorer (Observation Log) MK Stellar spectral classification in Morgan-Keenan system PLX Trigonometric parallaxes pm Proper motions (in 1950 equatorial frame) #pos Equatorial positions ROT Rotational velocities (V . sini) V* Data related to variable stars

The next sections provide more details about each data type included in SIMBAD.

3  diameter values

Stellar diameter values
Example:
diameter  | diameterQ unit| error   | filter | method |     Reference     |
----------------------------------------------------------------------------
diameter  | 3.15E-05  mas |0.10E-05 |B       |6A      |2001A&A...367..521P|
diameter  | 3E-01     mas |0.10E-01 |V       |3A      |2001A&A...367..521P|
diameter  | 0.000345: mas |0.000012 |U       |5A      |2001A&A...367..521P|
diameter  | 7.00E+05: km  |0.000012 |U       |5A      |2001A&A...367..521P|

 
Header Meaning


Diameter Diameter value Q quality code (':' for uncertain) unit unit of the diameter (mas or km) error error on the diameter value filter filter or wavelength method determination method reference bibliographic reference

4  object distance values

Object distance values
Example:
                    1         2         3         4         5         6
          01234567890123456789012345678901234567890123456789012345678901
distance  | distance Q unit |  err-   err+  | method |     Reference     |
------------------------------------------------------------------------
distance  |    17.3     Mpc | -0.2   +0.6   |ST-L    |2000A&A...356..849G|
distance  |   125.43    kpc | -0.12  +1.20  |Cep     |2000A&A...356..849G|
distance  |    12.345   pc  | -0.015 +0.040 |RRLyr   |2008MNRAS.383..750C|
distance  |   334       pc  |-22    +25     |paral   |2008MNRAS.383..750C|

 
Header Meaning


distance Distance value Q quality code unit distance unit (pc, kpc, Mpc) err- minus error on the distance value err+ plus error on the distance value method determination method reference bibliographic reference

5  Fe/H Measurements

Stellar parameters (Teff, log(g) and [Fe/H]) taken from the literature.

Example:

         1         2         3         4         5         6
12345678901234567890123456789012345678901234567890123456789012
Fe_h | Teff log.g|[Fe/H]*|CompStar |CatNo|    Reference      |
--------------------------------------------------------------
Fe_h | 5196  4.5 |-1.40 M|SUN      |F4716|1991ApJS...77..515L|

Details of column meaning:

 
Header Meaning


Teff The effective temperature Teff, in °K

log.g The decimal logarithm of the surface gravity expressed in cm/s2

[Fe/H] The metallicity index relative to the Sun, in a log scale:
[Fe/H] = log(Fe/H)* –log(Fe/H)(sun)
A value of [Fe/H] = –1.0 therefore means a metal abundance 10 times lower than the Sun, and a value of [Fe/H] = +0.3 a metal abundance 2 times higher than the Sun.

[Fe/H] flag (*) is a flag on the [Fe/H] value which can take the following values:

	S  result from a spectrum of low signal to noise ratio 
	M  average of several values given in the corresponding article
	C  in the absence of any indication in the corresponding article,
		  [Fe/H] relative to the Sun was calculated with a solar value
		  of 7.50 
	T  indicates that both M and C apply 
	D  indicates that both S and C apply 
        

CompStar designates the comparison star from which the [Fe/H] value was obtained.

CatNo identifies the star in the Cayrel et al. (1997A&AS..124..299C) compilation: it is made of the letter F or C for Field or Cluster star, followed by the ordinal record number in the Field star table (Table 1) or the Cluster star table (Table 2)

Reference Reference (bibcode) of the measurement


6  IUE measurements

Example:
         1         2         3         4         5         6         7
123456789012345678901234567890123456789012345678901234567890123456789012
 |Homogenized Name: ComplID    |PROG |CL|D CAM IMAGE A|  FES MD|Obs.date Time|ExpTim|m|CEB|S|Comments            |F|Reference          |
----------------------------------------------------------------------------------------------------------------------------------------
 |HD 93308        :WE          |NDEKD|61|L LWR 14605 L|      BO|821112 001100|003000| |3X1|G|E=2X,C=110,B=30     |*|1996IUEML.C......0I|

 
Header Meaning


Homogenized Name: ComplID Homogenized target identifier, followed by a complement indicator for off-target spectra, or part of extended objects (e.g. SW for South-West) PROG Observing Program Identification CL Classification of IUE Target (see table of classes below) D CAM IMAGE A Dispersion, Camera, Image, Aperture form the observation Identifier. Dispersion is Low or High Camera is LWP, LWR, SWP or SWR for Long Wavelength Prime camera, Long Wavelength Redundant camera, Short Wavelength Prime camera and Short Wavelength Prime camera; Image is the image number Aperture is Large (10x20'') or Small (3'') FES MD is the count and mode. Photon counts are averaged over an integration time dependent on the needs of target acquisition; note that the FES detector saturates at a count of 28673 ! Mode is FU for fast track/Underlap, FO for fast track/Overlap, and SO for slow track/Overlap. Obs.date Time Observation start ExpTim Exposure time (s) m Abnormality Code, as follows:
        A = Abnormal READ (ABNREAD) 
         B = BAD Scans LWP (ABNBADSC) 
         C = CORRUPTION including 159 DN 
         H = History Play back (ABNHISTR) 
         M = Missing THDA, any of THDAEND, THDAREAD, or THDASTRT 
         N = Non-standard image acquisition ABNNOSTD 
         O = OFFSET from nucleus; from center; etc. 
         P = Readmode = PARTIAL 
         R = REMNANT of previous spectrum visible 
         S = Serendipity Exposure 
         T = TRACK LOST 
         U = UVC voltage other than -5Kev 
         W = ABNHTRWU = LWR Heater Warm Up 
         Z = contamination by solar spectrum or extended source 
         8 = Cross-correlation less than 80	
CEB Exposure class made of 3 characters related to Continuum, Exposure, Background with meaning:    
           0 =   0 < dn <  20 
        1 =  21 < dn <  30 
        2 =  31 < dn <  40 
        3 =  41 < dn <  50 
        4 =  51 < dn <  60 
        5 =  61 < dn <  70 
        6 =  71 < dn <  80 
        7 =  81 < dn <  90 
        8 =  91 < dn < 100 
        9 = 101 < dn < ... 
        X = saturated 
    
S Observation Station as Goddard or Vilspa Comments Other comments related to the observation F always *, spectrum accessible Reference Reference (bibcode) of the measurement

|
List of IUE Classifications | |

00 Sun 50 R, N or S types 01 Earth 51 Long Period Variable Stars 02 Moon 52 Irregular Variables 03 Planet 53 Regular Variables 04 Planetary satellite 54 Dwarf Novae 05 Minor Planet 55 Classical Novae 06 Comet 56 Supernovae 07 Interplanetary medium 57 Symbiotic Stars 08 Giant Red Spot 58 T Tauri 59 X-Ray 10 WC 60 Shell Star 11 WN 61 Eta Carinae 12 Main Sequence O 62 Pulsar 13 Supergiant O 63 Nova-like 14 Oe 64 Other stellar Object 15 Of 65 Misidentified targets 16 sdO 66 Interacting Binaries 17 WD O 19 UV-strong 20 B0-B2 V-IV 70 Planetary Nebula + Central Star 21 B3-B5 V-IV 71 Planetary Nebula - Central Star 22 B6-B9,5 V-IV 72 H II Region 23 B0-B2 III-I 73 Reflection Nebula 24 B3-B5 III-I 74 Dark Cloud (absorption spectrum) 25 B6-B9.5 III-I 75 Supernova Remnant 26 Be 76 Ring Nebula (shock-ionised) 27 Bp 28 sdB 29 WDB 30 A0-A3 V-IV 80 Spiral Galaxy 31 A4-A9 V-IV 81 Elliptical Galaxy 32 A0-A3 III-I 82 Irregular Galaxy 33 A4-A9 III-I 83 Globular Cluster 34 Ae 84 Seyfert Galaxy 35 Am 85 Quasar 36 Ap 86 Radio Galaxy 37 WDA 87 BL Lacertae object 38 Horizontal Branch 88 Emission Line Galaxy (non-Seyfert) 39 Composite 40 F0-F2 90 Intergalactic Medium 41 F3-F9 42 Fp 43 Late Type Degenerate Stars 44 G IV-VI 45 G I-III 46 K IV-VI 47 K I-III 48 M Dwarfs 49 M I-III 99 Nulls and Flat Fields

7  MK measurements

This section includes MK classifications in the Morgan-Keenan system from bibliographical surveys (e.g. by Jaschek M.), as well as the Michigan Catalogues of Two-Dimensional Spectral Types for the HD stars (Houk N., 1975, and seq.).

Example:
         1         2         3         4         5         6
123456789012345678901234567890123456789012345678901234567890123456789
MK  |ds/mss Spectral type                       |     reference     |
---------------------------------------------------------------------
MK m|  /    G2Ibvar                             |1954ApJS....1..175B|

 
Header Meaning


ds/mss Brief description of the dispersive system used:
 
P prism G grating S slit spectrograph OP objective prism MS Michigan Spectral Survey
For MS data, a quality index is included , in the range [1...4] from good to poor, and further notes:
 
+ the spectral type was found in the literature X overlapping spectra A averaged spectral classification

Spectral type Spectral classification in the MK system reference source of the spectral classification

8  PLX measurements

This section groups measurements of trigonometric parallaxes.

Example:
         1         2         3
1234567890123456789012345678901234567
PLX  | plx  :p.e|     reference     |
-------------------------------------
PLX  |  .005:004|1952$YUO.1952.....J|

 
Header Meaning


plx : p.e Trigonometric parallax π (''), and probable error (in 10–3 arcsec) reference source of the parallax

9  PM measurements

This section groups all measurements of stellar proper motions, with the exception of SAO catalogue, listed separately. These data are presently given at equinox and epoch 1950, in the FK4 system.

Example:
         1         2         3         4         5
1234567890123456789012345678901234567890123456789012345
PM  | pm-ra [ m.e ]| pm-de [ m.e ]|Sys.|     reference     |
-------------------------------------------------------
PM  |  -.026[ .015]|  +.025[ .012]|FK4 |1971$AGK3.C.......L|

 
Header Meaning


pm-ra [m.e.] µα. cosδ in mas/yr, and σ within square bracket pm-dec[m.e.] µδ in mas/yr, and σ within square bracket Sys. Astrometric system used, which can be FK4, FK5 or ICRS reference source of the proper motions

10  ROT measurements

Stellar Rotational Velocities.

               1         2         3         4
     012345678901234567890123456789012345678901234
ROT  | Vsini  [ err ] (mes)|Q|    reference      |
--------------------------------------------------
ROT  | 9      [     ] ( 10)|E|1970CoKwa.189....0U|
ROT  |<125.12 [10.10] (   )|A|1995ApJS...99..135A|

 
Header Meaning


Vsini projected rotational velocity   v sini (km/s) [err] error on the rotaional velocity (mes) number of measurements Q quality code (from A: best .. E: unknown origin) reference source of the rotational velocity

11  RVEL measurements

This section deals with radial velocities of galaxies.

Example:
         1         2         3         4         5
12345678901234567890123456789012345678901234567890123
RVEL   | Rvel   (nmes)| rem |dis|     reference     | 
-----------------------------------------------------
RVEL m|   +5100 (    )|     |   |1973UGC...C.......N|

 
Header Meaning


Rvel (nmes) radial velocity (km/s), and number of measurements reference bibliographic reference

12  V* measurements

Parameters concerning the variable stars were extracted mainly from the General Catalog of Variable Stars by Kukarkin et al. USSR Academy of Sciences (3rd edition in 1969, and continuations).

Example:
         1         2         3         4         5         6         7         8
1234567890123456789012345678901234567890123456789012345678901234567890123456789012345
V*  |vartyp| Vmax   p   Vmin | period (d)  |  epoch (JD)  |D/rt%|Reference          |
-------------------------------------------------------------------------------------
V* m|Cd    |  3.90  B   5.09 |     5.3663  | 2427628.86   |30.0 |1969$GCVS.C03.....K|

 
Header Meaning


Typ Type of variability, summarized below Max, p, min Maximum and minimum of brightness; p specifies the type of magnitudes P(d) period (in days) Ep(JD) epoch (in Julian Days), which corresponds to: D/rt(%) Duration of eclipse for Algol type stars;
Raising time for all other variable types Reference source of data

The classification defined in the 3rd Edition is:

 
ACV α2 CVn    IS Rapid Irregular BCEP β Cep L slow irregular BLLAC BL Lac LB slow late-type irregular BY BY Dra M Mira CEP Long-period Cepheid N Nova CST constant NL nova–like CW W Vir QSO Quasar DCEP δ Cep (Classical Cepheid) RCB R CrB DSCT δ Sct RR RR Lyr E Eclipsing binary RRC RR Lyr, P ≃0.3d EA Algol-type eclipsing binary RV RV Tau (supergiants) EB β Lyr–type eclipsing bin. S rapid variable ELL ellipsoidal SDOR S Dor EW W UMa–type eclipsing binary SR semi-regular GCAS γ Cas SN Supernova I Irregular UG U Gem IA Irregular of early type UV UV Cet (flare) IN Irregular in nebula UVN UV Cet in nebula INS Rapid irregular in nebula ZAND Z And symbiotic star INT T Tau irregular ZCAM Z Cam ZZC ZZ Cet


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